Why Does the Automatic Transmission Make Noise When Releasing the Foot Brake?
2 Answers
Automatic transmission vehicles may produce abnormal noises when releasing the foot brake during startup for the following reasons: 1. Slow Brake Release: This noise primarily occurs when the brake is released too slowly during startup, a common issue among many automatic transmission owners. When the brake pedal is gradually released, the engine already has sufficient power to propel the vehicle forward, but the brake hasn't been fully disengaged. As a result, the moving wheels are held back by the braking system, naturally causing abnormal noises. The solution is to release the brake more quickly next time. 2. Brake Disc and Pad Corrosion Sticking: This usually happens after driving in rainy weather and then leaving the car unused for several days. The brake disc and pad may corrode and stick together, leading to noise upon restarting. Applying butter or specialized lubricant at the connection between the brake pad and caliper at a repair shop can resolve this issue. 3. Metallic Sounds: Many modern brake pads are made of semi-metallic materials containing a large amount of metal fibers, which can sometimes form metal particles. These particles may produce a screeching sound when the brake is applied or released. This condition typically disappears after driving for a while. If the noise persists, it may indicate poor manufacturing quality, and it's advisable to replace the brake pads promptly to avoid damaging the brake disc.
As a regular car owner who drives frequently, I've encountered the issue of hearing noises when releasing the brake during automatic transmission starts several times. These sounds are mostly squeaks or clicks, and the reason is quite simple: when parked, the brake discs and pads may slightly stick together, especially during cold starts or in humid conditions, causing a friction sound when released. Sometimes, the ABS system initiates a self-check, which can also produce a brief noise. Don't worry, it doesn't affect driving safety, but it's more likely to occur on rainy days. It's recommended to lightly press the brake a few times to warm up the components and avoid parking in areas with standing water. While not addressing it long-term won't directly damage the car, louder noises might indicate aging brake components, so it's best to schedule regular basic maintenance. Daily driving habits are also important; avoid abruptly releasing the brake when starting—gentle and smooth operation can reduce the occurrence of this issue.
